Terminal device, base station device, integrated circuit, and communication method

ABSTRACT

A terminal device configured to communicate with a base station device includes: a reception unit configured to receive information indicating that more than five downlink carriers are configured, and information indicating the number of cells in which the terminal device is capable of simultaneously monitoring physical downlink control channels; and a monitoring unit configured to monitor physical downlink control channels of only cells specified by the information indicating the number of cells in which the terminal device is capable of simultaneously monitoring physical downlink control channels.

TECHNICAL FIELD

The present invention relates to a terminal device, a base stationdevice, an integrated circuit, and a communication method.

This application claims priority based on Japanese Patent ApplicationNo. 2015-014991 filed on Jan. 29, 2015, the contents of which areincorporated herein by reference.

BACKGROUND ART

In the 3rd Generation Partnership Project (3GPP), a radio access methodand a radio network for cellular mobile communications (hereinafterreferred to as “Long Term Evolution (LTE)”, or “Evolved UniversalTerrestrial Radio Access (EUTRA)”) have been studied. In LTE, a basestation device is also referred to as an evolved NodeB (eNodeB), and aterminal device is also referred to as user equipment (UE). LTE is acellular communication system in which an area is divided into multiplecells to form a cellular pattern, each of the cells being served by abase station device. A single base station device may manage multiplecells.

LTE supports a time division duplex (TDD). LTE that employs a TDD schemeis also referred to as TD-LTE or LTE TDD. Uplink signals and downlinksignals are time division multiplexed in TDD. LTE also supports afrequency division duplex (FDD).

In 3GPP, career aggregation has been specified which allows a terminaldevice to perform simultaneous transmission and/or reception in up tofive serving cells (component careers).

In 3GPP, a configuration where a terminal device performs simultaneoustransmission and/or reception in more than five serving cells (componentcareers) has been considered (NPL 1). Furthermore, a configuration wherea terminal device transmits a physical uplink control channel in asecondary cell which is a serving cell other than a primary cell hasbeen considered (NPL 1).

CITATION LIST Non-Patent Literature

NPL 1: “New WI proposal: LTE Carrier Aggregation Enhancement Beyond 5Carriers”, RP-142286, Nokia Corporation, NTT DoCoMo Inc., NokiaNetworks, 3GPP TSG RAN Meeting #66, Hawaii, United States of America,8-11 Dec. 2014.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, for the above-described radio systems, a concrete method whentransmitting downlink control information has not been sufficientlydiscussed.

The present invention provides a terminal device, an integrated circuitmounted on the terminal device, a communication method used by theterminal device, a base station device, an integrated circuit mounted onthe base station device, and a communication method used by the basestation device that allow downlink control information to be transmittedefficiently.

Means for Solving the Problems

(1) A terminal device according to one aspect of the present inventionis a terminal device including: a reception unit configured to receiveinformation indicating that more than five downlink carriers areconfigured and information indicating the number of cells in which theterminal device is capable of simultaneously monitoring physicaldownlink control channels; and a monitoring unit configured to monitorphysical downlink control channels of cells specified by the informationindicating the number of cells in which the terminal device is capableof simultaneously monitoring physical downlink control channels.

(2) A terminal device according to one aspect of the present inventionis a terminal device including: a reception unit configured to receiveinformation indicating that more than five downlink carriers areconfigured and information indicating the number of downlink cellscapable of being activated simultaneously; a medium access control (MAC)layer processing unit configured to activate downlink cells inaccordance with the information indicating the number of downlink cellscapable of being activated simultaneously; and a monitoring unitconfigured to monitor physical downlink control channels of cellsactivated by the medium access control (MAC) layer processing unit.

(3) A base station device according to one aspect of the presentinvention is a base station device including: a transmission unitconfigured to transmit information indicating that more downlinkcarriers are configured and information indicating the number of cellsin which a terminal device is capable of simultaneously monitoringphysical downlink control channels; and a physical downlink controlchannel transmission unit configured to transmit physical downlinkcontrol channels of cells specified by the information indicating thenumber of cells in which the terminal device is capable ofsimultaneously monitoring physical downlink control channels.

(4) A base station device according to one aspect of the presentinvention is a base station device including: a transmission unitconfigured to transmit information indicating that more than fivedownlink carriers are configured and information indicating the numberof downlink cells capable of being activated simultaneously; a mediumaccess control (MAC) layer processing unit configured to activatedownlink cells in accordance with the information indicating the numberof downlink cells capable of being activated simultaneously; and aphysical downlink control channel transmission unit configured totransmit physical downlink control channels of cells activated by themedium access control (MAC) layer processing unit.

(5) A communication method according to one aspect of the presentinvention is a communication method for a terminal device. Thecommunication method includes the steps of: receiving informationindicating that more than five downlink carriers are configured andinformation indicating the number of cells in which the terminal deviceis capable of simultaneously monitoring physical downlink controlchannels; and monitoring physical downlink control channels of cellsspecified by the information indicating the number of cells in which theterminal device is capable of simultaneously monitoring physicaldownlink control channels.

(6) A terminal device according to one aspect of the present inventionis a communication method for a terminal device. The communicationmethod includes the steps of: receiving information indicating that morethan five downlink carriers are configured and information indicatingthe number of downlink cells capable of being activated simultaneously;activating downlink cells in accordance with the information indicatingthe number of downlink cells capable of being activated simultaneously;and monitoring physical downlink control channels of the activatedcells.

(7) A communication method according to one aspect of the presentinvention is a communication method for a base station device. Thecommunication method includes the steps of: transmitting informationindicating that more than five downlink carriers are configured andinformation indicating the number of cells in which a terminal device iscapable of simultaneously monitoring physical downlink control channels;and transmitting physical downlink control channels of cells specifiedby the information indicating the number of cells in which the terminaldevice is capable of simultaneously monitoring physical downlink controlchannels.

(8) A communication method according to one aspect of the presentinvention is a communication method for a base station device. Thecommunication method includes the steps of: transmitting informationindicating that more downlink carriers are configured and informationindicating the number of downlink cells capable of being activatedsimultaneously; activating downlink cells in accordance with theinformation indicating the number of downlink cells capable of beingactivated simultaneously; and transmitting physical downlink controlchannels of the activated cells.

(9) An integrated circuit according to one aspect of the presentinvention is an integrated circuit mounted on a terminal device. Theintegrated circuit causes the terminal device to exert the functions of:receiving information indicating that more than five downlink carriersare configured and information indicating the number of cells in whichthe terminal device is capable of simultaneously monitoring physicaldownlink control channels; and monitoring physical downlink controlchannels of cells specified by the information indicating the number ofcells in which the terminal device is capable of simultaneouslymonitoring physical downlink control channels.

(10) An integrated circuit according to one aspect of the presentinvention is an integrated circuit mounted on a terminal device. Theintegrated circuit causes the terminal device to exert the functions of:receiving information indicating that more than five downlink carriersare configured and information indicating the number of downlink cellscapable of being activated simultaneously; activating downlink cells inaccordance with the information indicating the number of downlink cellscapable of being activated simultaneously, and monitoring only physicaldownlink control channels of the activated cells.

(11) An integrated circuit according to one aspect of the presentinvention is an integrated circuit mounted on a base station device. Theintegrated circuit causes the base station device to exert the functionsof: transmitting information indicating that more than five downlinkcarriers are configured and information indicating the number of cellsin which a terminal device is capable of simultaneously monitoringphysical downlink control channels; and transmitting physical downlinkcontrol channels of cells specified by the information indicating thenumber of cells in which the terminal device is capable ofsimultaneously monitoring physical downlink control channels.

(12) An integrated circuit according to one aspect of the presentinvention is an integrated circuit mounted on a base station device. Theintegrated circuit causes the base station device 3 to exert thefunctions of: transmitting information indicating that more than fivedownlink carriers are configured and information indicating the numberof downlink cells capable of being activated simultaneously; activatingdownlink cells in accordance with the information indicating the numberof downlink cells capable of being activated simultaneously, andtransmitting physical downlink control channels of the activated cells.

Effects of the Invention

According to the present invention, downlink control information can beexecuted efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a radio communication system accordingto the present embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a radioframe according to the present embodiment.

FIG. 3 is a diagram illustrating a configuration of a slot according tothe present embodiment.

FIG. 4 is a diagram illustrating one example of allocation of a physicalchannel and mapping of a physical signal to a downlink subframeaccording to the present embodiment.

FIG. 5 is a diagram illustrating one example of allocation of a physicalchannel and mapping of a physical signal to an uplink subframe accordingto the present embodiment.

FIG. 6 is a diagram illustrating one example of allocation of a physicalchannel and mapping of a physical signal to a special subframe accordingto the present embodiment.

FIG. 7 is a diagram illustrating one example of downlink cells in whicha physical downlink control channel/an enhanced physical downlinkcontrol channel is monitored under a condition where more than fivedownlink carriers are configured, according to the present embodiment.

FIG. 8 is a diagram illustrating one example of the downlink cells inwhich physical downlink shared channels can be received simultaneouslyunder a condition where more than five downlink carriers are configured,according to the present embodiment.

FIG. 9 is a diagram illustrating one example of activated downlink cellsunder a condition where more than five downlink carriers are configured,according to the present embodiment.

FIG. 10 is a diagram illustrating one example of a configuration whereresources on downlink shared channels are indicated via a downlinkcontrol channel under a condition where joint coding has been applied tomultiple downlink cells, according to the present embodiment.

FIG. 11 is a diagram illustrating one example of a configuration whereresources on downlink shared channels are indicated via downlink controlchannels under a condition where separate coding has been applied tomultiple downlink cells, according to the present embodiment.

FIG. 12 is a diagram illustrating one example of a configuration whereresources on downlink shared channels are indicated via a downlinkcontrol channel under a condition where joint coding has been applied tomultiple downlink cells for each cell group, according to the presentembodiment.

FIG. 13 is a schematic block diagram illustrating a configuration of aterminal device 1 according to the present embodiment.

FIG. 14 is a schematic block diagram illustrating a configuration of abase station device 3 according to the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below.

FIG. 1 is a conceptual diagram of a radio communication system accordingto the present embodiment. In FIG. 1, the radio communication systemincludes terminal devices 1A to 1C and a base station device 3. Theterminal devices 1A to 1C are each referred to as a terminal device 1below.

Carrier aggregation will be described below.

In the present embodiment, multiple serving cells are configured for theterminal device 1. A technology in which the terminal device 1communicates via the multiple cells is referred to as cell aggregationor carrier aggregation. The present invention may be applied to each ofthe multiple serving cells configured for the terminal device 1.Furthermore, the present invention may be applied to some of theconfigured multiple serving cells. Furthermore, the present inventionmay be applied to each of groups of the configured multiple servingcells. Furthermore, the present invention may be applied to some of thegroups of the configured multiple serving cells.

Time division duplex (TDD) and/or frequency division duplex (FDD) isapplied to a radio communication system according to the presentembodiment. For cell aggregation, TDD may be applied to all of themultiple serving cells. Alternatively, serving cells to which TDD isapplied and serving cells to which FDD is applied may be aggregated.

The configured multiple serving cells include one primary cell and oneor multiple secondary cells. The primary cell is a serving cell in whichan initial connection establishment procedure has been performed, aserving cell in which a connection re-establishment procedure has beenstarted, or a cell indicated as a primary cell during a handoverprocedure. At a point in time when a radio resource control (RRC)connection is established, or later, a secondary cell may be configured.

A carrier corresponding to a serving cell in the downlink is referred toas a downlink component carrier. A carrier corresponding to a servingcell in the uplink is referred to as an uplink component carrier. Thedownlink component carrier and the uplink component carrier arecollectively referred to as a component carrier.

The terminal device 1 can perform simultaneous transmission and/orreception on multiple physical channels in multiple serving cells(component careers). A single physical channel is transmitted in asingle serving cell (component carrier) of the multiple serving cells(component carriers).

In the present embodiment, a secondary cell used for transmission of aphysical uplink control channel (PUCCH) is referred to as a specialsecondary cell or a PUCCH secondary cell. In the present embodiment, asecondary cell not used for the transmission of the PUCCH is referred toas a non-special secondary cell, a non-PUCCH secondary cell, a non-PUCCHserving cell, or a non-PUCCH cell. The primary cell and the specialsecondary cell is collectively referred to as a PUCCH serving cell or aPUCCH cell.

The PUCCH serving cell (the primary cell, the PUCCH secondary cell)includes the downlink component carrier and the uplink componentcarrier. A resource for PUCCH is configured in the PUCCH serving cell(the primary cell, the PUCCH secondary cell).

The non-PUCCH serving cell (non-PUCCH secondary cell) may include onlythe downlink component carrier. The non-PUCCH serving cell (non-PUCCHsecondary cell) may include the downlink component carrier and theuplink component carrier.

The terminal device 1 performs transmission on the PUCCH in the PUCCHserving cell. The terminal device 1 performs transmission on the PUCCHin the primary cell. The terminal device 1 performs transmission on thePUCCH in the special secondary cell. The terminal device 1 does notperform transmission on the PUCCH in the non-special secondary cell.

Note that the special secondary cell may be defined as a serving cellother than the primary cell or the secondary cell.

Physical channels and physical signals according to the presentembodiment will be described.

In FIG. 1, uplink radio communication from the terminal device 1 to thebase station device 3 uses the following uplink physical channels. Theuplink physical channels are used to transmit information output from ahigher layer.

-   -   Physical uplink control channel (PUCCH)    -   Physical uplink shared channel (PUSCH)    -   Physical random access channel (PRACH)

The PUCCH is used to transmit uplink control information (UCI). Theuplink control information includes: downlink channel state information(CSI): a scheduling request (SR) indicating a request for a PUSCHresource; and a hybrid automatic repeat request acknowledgement(HARQ-ACK) for downlink data (a transport block, a medium access controlprotocol data unit (MAC PDU), a downlink-shared channel (DL-SCH), or aphysical downlink shared channel (PDSCH)). The HARQ-ACK indicates anacknowledgement (ACK) or a negative-acknowledgement (NACK). The HARQ-ACKis also referred to as ACK/NACK, HARQ feedback, HARQ acknowledge, HARQinformation, or HARQ control information.

The PUSCH is used to transmit uplink data (uplink-shared channel(UL-SCH)). Furthermore, the PUSCH may be used to transmit the HARQ-ACKand/or channel state information along with the uplink data.Furthermore, the PUSCH may be used to transmit only the channel stateinformation or to transmit only the HARQ-ACK and the channel stateinformation.

The PRACH is used to transmit a random access preamble. The PRACH isused for the initial connection establishment procedure, the handoverprocedure, the connection re-establishment procedure, synchronization(timing adjustment) for uplink transmission, and the request for thePUSCH resource.

In FIG. 1, the following uplink physical signal is used in the uplinkradio communication. The uplink physical signal is not used to transmitinformation output from the higher layer, but is used by a physicallayer.

-   -   Uplink reference signal (UL RS)

According to the present embodiment, the following two types of uplinkreference signals are used.

-   -   Demodulation reference signal (DMRS)    -   Sounding reference signal (SRS)

The DMRS relates to transmission of the PUSCH or the PUCCH. The DMRS istime-multiplexed with the PUSCH or the PUCCH. The base station device 3uses the DMRS in order to perform channel compensation of the PUSCH orthe PUCCH. Transmission of both of the PUSCH and the DMRS is hereinafterreferred to simply as transmission of the PUSCH. Transmission of both ofthe PUCCH and the DMRS is hereinafter referred to simply as transmissionof the PUCCH.

The SRS is not associated with the transmission of the PUSCH or thePUCCH. The base station device 3 uses the SRS in order to measure anuplink channel state.

In FIG. 1, the following downlink physical channels are used fordownlink radio communication from the base station device 3 to theterminal device 1. The downlink physical channels are used to transmitthe information output from the higher layer.

-   -   Physical broadcast channel (PBCH)    -   Physical control format indicator channel (PCFICH)    -   Physical hybrid automatic repeat request indicator channel        (PHICH)    -   Physical downlink control channel (PDCCH)    -   Enhanced physical downlink control channel (EPDCCH)    -   Physical downlink shared channel (PDSCH)    -   Physical multicast channel (PMCH)

The PBCH is used to broadcast a master information block (MIB), or abroadcast channel (BCH), that is shared by the terminal devices 1.

The PCFICH is used to transmit information indicating a region (OFDMsymbols) to be used for transmission of the PDCCH.

The PHICH is used to transmit an HARQ indicator (HARQ feedback orresponse information) indicating an acknowledgement (ACK) or a negativeacknowledgement (NACK) with respect to the uplink data (uplink sharedchannel (UL-SCH)) received by the base station device 3.

The PDCCH and the EPDCCH are used to transmit downlink controlinformation (DCI). The downlink control information is also referred toas a DCI format. The downlink control information includes DCI format 3,DCI format 3A, a downlink grant and an uplink grant. The downlink grantis also referred to as downlink assignment or downlink allocation.

The downlink grant is used for scheduling of a single PDSCH within asingle cell. The downlink grant is used for scheduling of the PDSCHwithin the same subframe as the subframe in which the downlink grant istransmitted.

The uplink grant is used for scheduling of a single PUSCH within asingle cell. The uplink grant is used for scheduling of a single PUSCHwithin the fourth or later subframe from the subframe in which theuplink grant is transmitted.

The uplink grant includes a TPC command for the PUSCH.

CRC parity bits added to the downlink grant or the uplink grant arescrambled with an RNTI. Specifically, the cyclic redundancy check (CRC)parity bits are added to the downlink grant or the uplink grant, andafter the addition, the CRC parity bits are scrambled with the RNTI.Here, the CRC parity bits added to the downlink grant or the uplinkgrant may be obtained from a payload of the DCI format.

The terminal device 1 attempts to decode the DCI format to which the CRCparity bits scrambled with the RNTI have been added, and detects the DCIformat for which the CRC is succeeded, as a DCI format addressed to theterminal device 1 itself (also referred to as blind decoding). In otherwords, the terminal device 1 detects the PDCCH with the CRC scrambledwith the RNTI. The terminal device 1 detects the PDCCH with the DCIformat to which the CRC parity bits scrambled with the RNTI have beenadded.

The RNTI includes a cell-radio network temporary identifier (C-RNTI).The C-RNTI is an identifier unique to the terminal device 1 and used foridentification of an RRC connection and scheduling. The C-RNTI is usedfor unicast transmission scheduled dynamically.

The RNTI also includes a semi-persistent scheduling C-RNTI (SPS C-RNTI).The SPS C-RNTI is an identifier unique to the terminal device 1 and usedfor semi-persistent scheduling. The SPS C-RNTI is used for unicasttransmission scheduled semi-persistently.

The RNTI further includes a random access RNTI (RA-RNTI). The RA-RNTI isan identifier used for transmission of a random access response message.In other words, the RA-RNTI is used for the transmission of the randomaccess response message in a random access procedure. For example, theterminal device 1 monitors the PDCCH with the CRC scrambled with theRA-RNTI after the transmission of a random access preamble. The terminaldevice 1 receives a random access response on the PDSCH in accordancewith detection of the PDCCH with the CRC scrambled with the RA-RNTI.

The RNTI further includes a paging RNTI (P-RNTI). The P-RNTI is anidentifier used for paging and notification of system informationmodification. For example, the P-RNTI is used for paging andtransmission of a system information message. The terminal device 1receives paging on the PDSCH in accordance with detection of the PDCCHwith the CRC scrambled with the P-RNTI.

The RNTI further includes a system information RNTI (SI-RNTI). TheSI-RNTI is an identifier used for broadcast of the system information.For example, the SI-RNTI is used for transmission of the systeminformation message. The terminal device 1 receives the systeminformation message on the PDSCH in accordance with detection of thePDCCH with the CRC scrambled with the SI-RNTI.

The RNTI further includes a temporary C-RNTI. The temporary C-RNTI is anidentifier used in a random access procedure. For example, the temporaryC-RNTI can be applied to a contention based random access procedure. Thetemporary C-RNTI can be applied when a valid C-RNTI is not available.For example, the terminal device 1 performs reception on the PDSCH inaccordance with detection of the PDCCH with the CRC scrambled with thetemporary C-RNTI.

The PDSCH is used to transmit downlink data (downlink shared channel(DL-SCH)). The DL-SCH is a transport channel. In other words, the DL-SCHtransmitted on the PDSCH is the transport channel associated with thePDCCH and/or the RNTI.

The PMCH is used to transmit multicast data (multicast channel (MCH)).

In FIG. 1, the following downlink physical signals are used in thedownlink radio communication. The downlink physical signals are not usedto transmit the information output from the higher layer, but are usedby the physical layer.

-   -   Synchronization signal (SS)    -   Downlink reference signal (DL RS)

The synchronization signal is used in order for the terminal device 1 tobe synchronized in terms of frequency and time domains for downlink. Inthe TDD scheme, the synchronization signal is mapped to subframes 0, 1,5, and 6 within a radio frame. In the FDD scheme, the synchronizationsignal is mapped to subframes 0 and 5 within the radio frame.

The downlink reference signal is used in order for the terminal device 1to perform the channel compensation on the downlink physical channel.The downlink reference signal is used in order for the terminal device 1to calculate the downlink channel state information.

According to the present embodiment, the following five types ofdownlink reference signals are used.

-   -   Cell-specific reference signal (CRS)    -   UE-specific reference signal (URS) associated with the PDSCH    -   Demodulation reference signal (DMRS) associated with the EPDCCH    -   Non-zero power channel state information-reference signal (NZP        CSI-RS)    -   Zero power channel state information-reference signal (ZP        CSI-RS)    -   Multimedia broadcast and multicast service over single frequency        network reference signal (MBSFN RS)    -   Positioning reference signal (PRS)

The downlink physical channels and the downlink physical signals arecollectively referred to as a downlink signal. The uplink physicalchannels and the uplink physical signals are collectively referred to asan uplink signal. The downlink physical channels and the uplink physicalchannels are collectively referred to as a physical channel. Thedownlink physical signals and the uplink physical signals arecollectively referred to as a physical signal.

The BCH, the MCH, the UL-SCH, and the DL-SCH are transport channels. Achannel used in a medium access control (MAC) layer is referred to as atransport channel. The unit of the transport channel used in the MAClayer is also referred to as a transport block (TB) or a MAC protocoldata unit (PDU). Control of a hybrid automatic repeat request (HARQ) isperformed on each transport block in the MAC layer. The transport blockis a unit of data that the MAC layer delivers to the physical layer. Inthe physical layer, the transport block is mapped to a codeword, andcoding processing is performed on a codeword-by-codeword basis.

In the present embodiment, a group of the multiple serving cells isreferred to as a PUCCH cell group. A certain serving cell belongs to anyone of PUCCH cell groups.

A single PUCCH cell group includes one PUCCH serving cell. A singlePUCCH cell group may include only one PUCCH serving cell. A single PUCCHcell group may include one PUCCH serving cell and one or multiplenon-PUCCH serving cells.

The PUCCH cell group including the primary cell is referred to as aprimary PUCCH cell group. The PUCCH cell group not including the primarycell is referred to as a secondary PUCCH cell group. In other words, thesecondary PUCCH cell group includes a PUCCH secondary cell.

An index for identifying the PUCCH cell group (a cell group index) maybe defined.

The index for the primary PUCCH cell group is always zero.

The index for the secondary PUCCH cell group is configured by a networkdevice (the base station device 3).

The PUCCH of the PUCCH serving cell is used in order to transmit uplinkcontrol information (the HARQ-ACK and/or the CSI) with respect to theserving cell (the PUCCH serving cell, the non-PUCCH serving cell)included in the PUCCH cell group to which the PUCCH serving cellbelongs.

In other words, the uplink control information (the HARQ-ACK and/or theCSI) with respect to the serving cell (the PUCCH serving cell, thenon-PUCCH serving cell) included in the PUCCH cell group is transmittedon the PUCCH of the PUCCH serving cell included in the PUCCH cell group.

The present embodiment may be applied to only the HARQ-ACK. The presentembodiment may be applied to only the CSI. The present embodiment may beapplied to the HARQ-ACK and the CSI. The PUCCH cell group for theHARQ-ACK and the PUCCH cell group for the CSI may be definedindependently. The PUCCH cell group for the HARQ-ACK and the PUCCH cellgroup for the CSI may be in common.

A configuration of the radio frame according to the present embodimentwill be described below.

FIG. 2 is a diagram illustrating a schematic configuration of the radioframe according to the present embodiment. Each of the radio frames is10 ms in length. In FIG. 2, the horizontal axis is a time axis.Furthermore, each of the radio frames is constituted of two half frames.Each of the half frames is 5 ms in length. Each of the half frames isconstituted of five subframes. Each of the subframes is 1 ms in lengthand is defined by two consecutive slots. Each of the slots is 0.5 ins inlength. The i-th subframe within a radio frame is constituted of the(2×i)-th slot and the (2×i+1)-th slot. To be more precise, 10 subframesare available in each 10 ins interval.

A single radio frame is constituted of at least a downlink subframe, anuplink subframe, and a special subframe.

The downlink subframe is a subframe reserved for downlink transmission.The uplink subframe is a subframe reserved for uplink transmission. Thespecial subframe is constituted of three fields. The three fields are adownlink pilot time slot (DwPTS), a guard period (GP), and an uplinkpilot time slot (UpPTS). The sum of lengths of the DwPTS, the GP, andthe UpPTS is 1 ms. The DwPTS is a field reserved for the downlinktransmission. The UpPTS is a field reserved for the uplink transmission.The GP is a field in which neither the downlink transmission nor theuplink transmission is performed. Moreover, the special subframe may beconstituted only of the DwPTS and the GP, or may be constituted only ofthe GP and the UpPTS.

A configuration of a slot according to the present embodiment will bedescribed below.

FIG. 3 is a diagram illustrating the configuration of the slot accordingto the present embodiment. According to the present embodiment, a normalcyclic prefix (CP) is applied to an OFDM symbol. Moreover, an extendedcyclic prefix (CP) may be applied to the OFDM symbol. The physicalsignal or the physical channel transmitted in each of the slots isexpressed by a resource grid. In FIG. 3, the horizontal axis is a timeaxis, and the vertical axis is a frequency axis. In downlink, theresource grid is defined by multiple subcarriers and multiple OFDMsymbols. In uplink, the resource grid is defined by multiple subcarriersand multiple SC-FDMA symbols. The number of subcarriers constituting oneslot depends on a cell bandwidth. The number of OFDM symbols or SC-FDMAsymbols constituting one slot is seven. Each element within the resourcegrid is referred to as a resource element. The resource element isidentified by a subcarrier number, and an OFDM symbol or SC-FDMA symbolnumber.

A resource block is used to express mapping of a certain physicalchannel (the PDSCH, the PDSCH, or the like) to resource elements. Forthe resource block, a virtual resource block and a physical resourceblock are defined. A certain physical channel is first allocated to thevirtual resource block. Thereafter, the virtual resource block is mappedto the physical resource block. One physical resource block is definedby seven consecutive OFDM symbols or SC-FDMA symbols in a time domainand by 12 consecutive subcarriers in a frequency domain. Therefore, onephysical resource block is constituted of (7×12) resource elements.Furthermore, one physical resource block corresponds to one slot in thetime domain and corresponds to 180 kHz in the frequency domain. Physicalresource blocks are numbered from 0 in the frequency domain.

The physical channel and the physical signal that are transmitted ineach of the subframes will be described below.

FIG. 4 is a diagram illustrating one example of allocation of thephysical channel and mapping of the physical signal to the downlinksubframe according to the present embodiment. In FIG. 4, the horizontalaxis is a time axis, and the vertical axis is a frequency axis. In thedownlink subframe, the base station device 3 may transmit the downlinkphysical channel (the PBCH, the PCFICH, the PHICH, the PDCCH, theEPDCCH, or the PDSCH), and the downlink physical signal (thesynchronization signal or the downlink reference signal). Moreover, thePBCH is transmitted only in subframe 0 within the radio frame. Moreover,the downlink reference signal is mapped to the resource elementsdistributed in the frequency domain and the time domain. The downlinkreference signal is not illustrated in FIG. 4 for the sake ofsimplicity.

Multiple PDCCHs may be frequency-multiplexed and time-multiplexed in aPDCCH region. Multiple EPDCCHs may be frequency-multiplexed,time-multiplexed, and spatial-multiplexed in an EPDCCH region. MultiplePDSCHs may be frequency-multiplexed and spatial-multiplexed in a PDSCHregion. The PDCCH, and the PDSCH or the EPDCCH may be time-multiplexed.The PDSCH and the EPDCCH may be frequency-multiplexed.

FIG. 5 is a diagram illustrating one example of the allocation of thephysical channel and the mapping of the physical signal to the uplinksubframe according to the present embodiment. In FIG. 5, the horizontalaxis is a time axis, and the vertical axis is a frequency axis. In theuplink subframe, the terminal device 1 may transmit the uplink physicalchannel (the PUCCH, the PUSCH or the PRACH) and the uplink physicalsignal (the DMRS or the SRS). In a PUCCH region, multiple PUCCHs arefrequency-multiplexed, time-multiplexed, and code-multiplexed. MultiplePUSCHs may be frequency-multiplexed and spatial-multiplexed in a PUSCHregion. The PUCCH and the PUSCH may be frequency-multiplexed. The PRACHmay be allocated to a single subframe or over two subframes.Furthermore, multiple PRACHs may be code-multiplexed.

The SRS is transmitted using the last SC-FDMA symbol within the uplinksubframe. To be more precise, the SRS is mapped to the last SC-FDMAsymbol within the uplink subframe. The terminal device 1 cannot transmitthe SRS and the PUCCH/PUSCH/PRACH at the same time in a single SC-FDMAsymbol in a single cell. In a single uplink subframe in a single cell,the terminal device 1 can transmit the PUSCH and/or the PUCCH using theSC-FDMA symbol except for the last SC-FDMA symbol within the uplinksubframe, and can transmit the SRS using the last SC-FDMA symbol withinthe uplink subframe. To be more precise, in a single uplink subframe ina single cell, the terminal device 1 can transmit both of the SRS andthe PUSCH/PUCCH. Moreover, the DMRS is time-multiplexed with the PUCCHor the PUSCH. The DMRS is not illustrated in FIG. 5 for the sake ofsimplicity.

FIG. 6 is a diagram illustrating one example of allocation of thephysical channel and mapping of the physical signal to the specialsubframe according to the present embodiment. In FIG. 6, the horizontalaxis is a time axis, and the vertical axis is a frequency axis. In FIG.6, the DwPTS is constituted of first to 10-th SC-FDMA symbols within thespecial subframe, the GP is constituted of 11-th and 12-th SC-FDMAsymbols within the special subframe, and the UpPTS is constituted of13-th and 14-th SC-FDMA symbols within the special subframe.

The base station device 3 may transmit the PCFICH, the PHICH, the PDCCH,the EPDCCH, the PDSCH, the synchronization signal, and the downlinkreference signal, in the DwPTS of the special subframe. The base stationdevice 3 does not transmit the PBCH in the DwPTS of the specialsubframe. The terminal device 1 may transmit the PRACH and the SRS inthe UpPTS of the special subframe. To be more precise, the terminaldevice 1 transmits none of the PUCCH, the PUSCH, and the DMRS in theUpPTS of the special subframe.

FIG. 7 is a diagram illustrating a configuration where more than fivedownlink cells are configured for the terminal device 1 according to thepresent embodiment.

In the present embodiment, for example, the career aggregation of up to32 downlink component carriers (downlink cells) may be supported asillustrated in FIG. 7. In other words, the base station device 3 and theterminal device 1 can perform simultaneous transmission and/or receptionon multiple physical channels in up to 32 serving cells. Here, thenumber of the uplink component careers may be less than the number ofthe downlink component careers.

In FIG. 7, according to the present embodiment, the downlink componentcareers are configured for the terminal device 1 in an RRC layer with aparameter (for example, SCellToAddMod-r13) indicating a component careerto be configured, and a list (for example, sCellToAddModList-r13) ofcomponent careers to be configured.

Furthermore, in the present embodiment, a parameter indicating thenumber of cells in which the terminal device 1 can monitor thePDCCHs/EPDCCHs simultaneously and the respective indexes of the cells(for example, SCellIndex-r13), or indexes of cells in which thePDCCHs/EPDCCHs can be monitored simultaneously (for example,SCellIndex-r13) may be configured from the configured list.

Furthermore, in the present embodiment, the number of cells in which theterminal device 1 can receive the PDSCHs simultaneously and therespective indexes of the cells (for example, SCellIndex-r13), orindexes of cells in which the PDSCHs can be received simultaneously (forexample, SCellIndex-r13) may be configured from the configured list.

FIG. 8 illustrates an example of a configuration where the downlinkcells that allow the terminal device to simultaneously receive PDSCHsare configured.

If the serving cell is the primary cell, or if the serving cell is thesecondary cell and the terminal device 1 is not configured to monitorthe PDCCH/EPDCCH with the CIF corresponding to the serving cell (thesecondary cell) in a different serving cell (the primary cell), theterminal device 1 receives the PDSCH of the serving cell via thePDCCH/EPDCCH.

The monitoring of the PDCCH/EPDCCH with the CIF refers to attempting todecode the PDCCH or the EPDCCH in accordance with the DCI formatincluding the CIF. The CIF is a field to which a carrier indicator ismapped. The value of the carrier indicator indicates the serving cell towhich the DCI format associated with the carrier indicator corresponds.

The terminal device 1 that is configured to monitor the PDCCH/EPDCCHwith the CIF corresponding to the serving cell in a different servingcell monitors the PDCCH/EPDCCH with the CIF in the different servingcell.

The terminal device 1 that is configured to monitor the PDCCH/EPDCCHwith the CIF corresponding to the serving cell in the different servingcell preferably receives the PDSCH for the serving cell via thePDCCH/EPDCCH in the different serving cell.

The terminal device 1 that is not configured to monitor the PDCCH/EPDCCHwith the CIF corresponding to the serving cell in the different servingcell monitors the PDCCH/EPDCCH with or without the CIF in the servingcell.

The terminal device 1 that is not configured to monitor the PDCCH/EPDCCHwith the CIF corresponding to the serving cell in the different servingcell preferably receives third information for the serving cell via thePDCCH/EPDCCH in the serving cell.

The PDCCH/EPDCCH for the primary cell is transmitted in the primarycell. The third information for the primary cell is preferablytransmitted on the PDCCH/EPDCCH in the primary cell.

The base station device 3 transmits, to the terminal device 1, aparameter (for example, cif-Presence) indicating whether or not the CIFis included in the DCI format transmitted in the primary cell.

For each secondary cell, the base station device 3 transmits, to theterminal device 1, a parameter (for example,CrossCarrierSchedulingConfig-r13) associated with cross carrierscheduling.

The parameter (for example, CrossCarrierSchedulingConfig-r13) includes aparameter (for example, schedulingCellInfo-r13) indicating whether thePDCCH/EPDCCH corresponding to an associated secondary cell istransmitted in the secondary cell or in a different serving cell.

When the parameter (for example, schedulingCellInfo-r13) indicates thatthe PDCCH/EPDCCH corresponding to the associated secondary cell istransmitted in the secondary cell, the parameter (for example,schedulingCellInfo-r13) includes a parameter (for example, cif-Presence)indicating whether or not the CIF is included in the DCI formattransmitted in the secondary cell.

When the parameter (for example, schedulingCellInfo-r13) indicates thatthe PDCCH/EPDCCH corresponding to the associated secondary cell istransmitted in a different serving cell, the parameter (for example,schedulingCellInfo-r13) includes a parameter (for example,schedulingCellId) indicating in which serving cell the downlinkallocation for the associated secondary cell is sent.

FIG. 9 illustrates, as another embodiment of the present invention, anexample of a configuration where the downlink cells capable of beingactivated simultaneously are configured.

In FIG. 9, the downlink component careers are configured for theterminal device 1 in the RRC layer with the parameter (for example,SCellToAddMod-r13) indicating a component career to be configured, andthe list (for example, sCellToAddModList-r13) of component careers to beconfigured.

Furthermore, the number of the downlink cells capable of being activatedsimultaneously may be configured for the terminal device 1 with aparameter for configuring the number of the downlink cells capable ofbeing activated simultaneously.

Note that the terminal device 1 may include information to be used forindicating the number of the downlink cells capable of being activatedsimultaneously (the number of downlink component careers) into thecapability of the terminal device (UE-EUTRA Capability, information oncapability) and transfer/transmit the information to the base stationdevice 3. In other words, the terminal device 1 may include theinformation to be used for indicating the number of downlink componentcareers capable of being activated simultaneously into the informationon capability and transmit the information. Here, the primary celland/or the PUCCH secondary cell may always be activated. For example,the terminal device 1 which supports activation of up to five downlinkcomponent careers including the primary cell may transmit information tobe used for indicating “4” or “5”, as the information to be used forindicating the number of downlink component careers capable of beingactivated simultaneously.

Note that the terminal device 1 may include information to be used forindicating the number of the uplink cells capable of being activatedsimultaneously (the number of uplink component careers) into thecapability of the terminal device (UE-EUTRA Capability, information oncapability) and transfer/transmit the information to the base stationdevice 3. In other words, the terminal device 1 may include theinformation to be used for indicating the number of uplink componentcareers capable of being activated simultaneously into the informationon capability and transmit the information.

In other words, the terminal device 1 may include the information to beused for indicating the number of PDCCHs that the terminal device 1 iscapable of receiving (capable of monitoring, capable of detecting)simultaneously in a subframe into the information on capability andtransmit the information. The terminal device 1 may include theinformation to be used for indicating the number of PDSCHs that theterminal device 1 is capable of receiving simultaneously in a subframeinto the information on capability and transmit the information. Forexample, the terminal device 1 may transmit information indicating thepossible combinations of physical channels that the terminal device 1 iscapable of receiving simultaneously in the downlink in a certainsubframe (the same subframe). Here, for example, the physical channelsmay include the PDCCH. The physical channels may include the EPDCCH. Thephysical channels may include the PDSCH. The physical channels mayinclude the PBCH. The physical channels may include the PMCH.

The terminal device 1 may transmit the information to be used forindicating the number of PDCCHs and/or the number of PDSCHs that theterminal device 1 is capable of receiving simultaneously in a subframe,for each RNTI to be monitored. For example, the terminal device 1 maytransmit the information to be used for indicating the number of PDCCHsand/or the number of PDSCHs that the terminal device 1 is capable ofreceiving simultaneously in a subframe, the PDCCHs having the CRCscrambled with the SI-RNTI added thereto and the PDSCHs being scheduledusing the PDCCHs. Here, the number of PDCCHs having the CRC scrambledwith the SI-RNTI added thereto may be one. The number of PDSCHsscheduled using the PDCCH may be one.

The terminal device 1 may transmit the information to be used forindicating the number of PDCCHs and/or the number of PDSCHs that theterminal device 1 is capable of receiving simultaneously in a subframe,the PDCCHs having the CRC scrambled with the RA-RNTI added thereto andthe PDSCHs being scheduled using the PDCCHs. Here, the number of PDCCHshaving the CRC scrambled with the RA-RNTI added thereto may be one. Thenumber of PDSCHs scheduled using the PDCCH may be one.

The terminal device 1 may transmit the information to be used forindicating the number of PDCCHs and/or the number of PDSCHs that theterminal device 1 is capable of receiving simultaneously in a subframe,the PDCCHs having the CRC scrambled with the temporary C-RNTI addedthereto and the PDSCHs being scheduled using the PDCCHs. Here, thenumber of PDCCHs having the CRC scrambled with the temporary C-RNTIadded thereto may be one. The number of PDSCHs scheduled using the PDCCHmay be one.

The terminal device 1 may transmit the information to be used forindicating the number of PDCCHs and/or the number of PDSCHs that theterminal device 1 is capable of receiving simultaneously in a subframe,the PDCCHs having the CRC scrambled with the C-RNTI and/or the SPSC-RNTI added thereto and the PDSCHs being scheduled using the PDCCHs.Here, the number of PDCCHs having the CRC scrambled with the SPS C-RNTIadded thereto may be one. The number of PDSCHs scheduled using the PDCCHmay be one. Here, the PDCCH having the CRC scrambled with the SPS C-RNTIadded thereto is used for scheduling of the PDSCH.

In other words, the terminal device 1 may transmit the information to beused for indicating the number of combinations of PDCCHs and PDSCHs thatthe terminal device 1 is capable of receiving simultaneously in asubframe, the PDCCHs having the CRC scrambled with the C-RNTI and/or theSPS C-RNTI added thereto. Here, the PDSCHs are scheduled via the PDCCHs.

The base station device 3 may activate downlink cells in the MAC layerin accordance with the configured number of downlink cells capable ofbeing activated simultaneously.

The terminal device 1 monitors the PDCCHs/EPDCCHs of the activatedcells, and receives the PDSCHs via the PDCCHs/EPDCCHs. In other words,the terminal device 1 monitors the PDCCHs/EPDCCHs in the activatedcells. The terminal device 1 does not monitor the PDCCH/EPDCCH in anydeactivated cell.

Here, the base station device 3 may activate or deactivate one ormultiple serving cells using a higher layer signal (for example, a MACcontrol element). For example, the mechanism of activation ordeactivation may be based on the combination of the MAC control elementand a timer (deactivation timer) associated with the deactivation.

Here, the base station device 3 may activate or deactivate individuallythe multiple secondary cells including the PUCCH secondary cell using asingle command (a single activation/deactivation command). In otherwords, the base station device 3 may transmit the single command to beused for activating or deactivating the secondary cells using the MACcontrol element.

As a value of the timer associated with the deactivation, a singlecommon value may be configured by the higher layer (for example, the RRClayer) for each terminal device 1. The timer (the value of the timer)associated with the deactivation may be held for each secondary cell.

The base station device 3 may transmit the higher layer signal includingthe timer associated with the deactivation for the secondary cell andinformation for configuration.

Note that the number of cells in which the PDCCHs/EPDCCHs can bemonitored simultaneously, the number of cells in which the PDSCHs can bereceived simultaneously, or the number of cells that can be activatedsimultaneously may not be configured for each downlink component career,but may be configured for each cell group (for example, the PUCCH cellgroup).

Next, FIG. 10 illustrates, as another embodiment, an example of aconfiguration where joint coding that indicates PDSCHs of multiple cellsthrough a PDCCH/EPDCCH is applied when the multiple downlink cells areconfigured.

In FIG. 10, for the base station device 3, downlink cells 5, 6 and 7 areat least configured and activated. The terminal device 1 monitors thePDCCH of the downlink cell 5, and receives the PDSCHs of the downlinkcells 5, 6 and 7 in accordance with the result of decoding the downlinkcontrol information (DCI). Note that the monitoring of the PDCCH of thedownlink cell 5 may be configured in the terminal device 1, for example,from second information in the RRC layer, or may be implicitlyconfigured from information configured as another parameter.

Although FIG. 10 illustrates an example using the PDCCH, the EPDCCH isalso applicable. The cell to be monitored by the terminal device 1 maybe the primary cell, or a cell configured in the secondary cell. Thecell may be the PUCCH cell in the cell group, and the terminal device 1may monitor only a cell including the PDCCH/EPDCCH on which joint codingis performed. Here, whether or not the joint coding is performed may beconfigured for the terminal device 1 through an RRC parameter, forexample, the third information.

Here, the terminal device 1 may monitor the PDCCH in the downlink cell5, and may receive the PDSCH in the downlink cell 5, the PDSCH in thedownlink cell 6, and the PDSCH in the downlink cell 7, in accordancewith the downlink control information. Alternatively, the terminaldevice 1 may monitor the PDCCH in the downlink cell 5, and receive asingle PDSCH over the downlink cell 5, the downlink cell 6, and thedownlink cell 7, in accordance with the downlink control information.

In other words, the DCI format used for the scheduling of the multiplePDSCHs in the multiple downlink cells may be defined as a downlinkcontrol information format. Here, the single PDSCH may be scheduled foreach of the multiple downlink cells by using the downlink controlinformation format. The DCI format used for the scheduling of the singlePDSCH over the multiple downlink cells may be defined as the downlinkcontrol information format. Here, the single PDSCH may be scheduled overthe multiple downlink cells by using the downlink control informationformat. Here, the downlink control information format used for thescheduling of the multiple PDSCHs in the multiple downlink cells, and/orthe downlink control information format used for the scheduling of thesingle PDSCH over the multiple downlink cells are also referred to asDCI format 6.

The PDCCH/EPDCCH used for transmission of DCI format 6 is also referredto as joint-coded PDCCH/EPDCCH (first PDCCH/EPDCCH). Alternatively,another name, such as DCI format 2E, may be used, but the followingdescription will be made using the name, DCI format 6. Monitoring of thefirst PDDCH/EPDCCH by the terminal device 1 is also referred to asmonitoring in accordance with the first PDDCH/EPDCCH. In other words,the monitoring in accordance with the first PDDCH/EPDCCH may includeattempting to decode the first PDDCH/EPDCCH. “Monitoring” refers toattempting to decode each PDCCH in a set of PDCCH candidates and/orattempting to decode each EPDCCH in a set of EPDCCH candidates, inaccordance with the monitored downlink control information format.

The multiple PDSCHs scheduled in accordance with a single DCI format 6may be configured by the base station device 3. For example, the basestation device 3 may configure the multiple PDSCHs scheduled inaccordance with a single DCI format 6 by configuring a serving cellindex corresponding to the multiple PDSCHs. For example, the basestation device 3 may configure the multiple PDSCHs scheduled inaccordance with a single DCI format 6, in accordance with informationincluded in the higher layer signal.

For example, the base station device 3 may transmit, for each servingcell, information for configuring the monitoring in accordance with thefirst PDCCH/EPDCCH to be performed (configuring DCI format 6 to bereceived), and information indicating that the PDSCH is to be scheduledin a certain serving cell.

For example, the base station device 3 may configure the monitoring inaccordance with the first PDCCH/EPDCCH to be performed for the downlinkcell 5. The base station device 3 may transmit information indicatingthat the first PDCCH/EPDCCH (alternatively, DCI format 6 may be used) tobe used for the scheduling of the PDSCH in the downlink cell 5 istransmitted in the downlink cell 5. The base station device 3 maytransmit information indicating that the first PDCCH/EPDCCH to be usedfor the scheduling of the PDSCH in the downlink cell 6 is transmitted inthe downlink cell 5. The base station device 3 may transmit informationindicating that the first PDCCH/EPDCCH to be used for the scheduling ofthe PDSCH in the downlink cell 7 is transmitted in the downlink cell 5.

Although FIG. 10 illustrates an example using the PDCCH, the EPDCCH isalso applicable. The cell to be monitored by the terminal device 1 maybe the primary cell, or a cell configured in the secondary cell. Thecell may be the PUCCH cell in the cell group, and the terminal device 1may monitor only a cell including a joint-coded PDCCH/EPDCCH. Here,whether or not the joint coding is performed may be configured for theterminal device 1 through the RRC parameter.

FIG. 11 illustrates an example of a configuration where the PDSCHs arereceived via the PDCCHs/EPDCCHs that are configured for each cell ratherthan being joint-coded. In other words, as described above, the DCIformat used for the scheduling of a single PDSCH in a single downlinkcell may be defined as the DCI format (for example, the DCI format maybe defined as DCI format 1 or DCI format 1A). Each PDCCH/EPDCCH used fortransmission of the DCI format that is used for the scheduling of thesingle PDSCH in the single downlink cell is also referred to as aseparate-coded PDCCH/EPDCCH (second PDCCH/EPDCCH). Monitoring of thesecond PDDCH/EPDCCH by the terminal device 1 is also referred to asmonitoring in accordance with the second PDDCH/EPDCCH. In other words,the monitoring in accordance with the second PDDCH/EPDCCH may includeattempting to decode the second PDDCH/EPDCCH.

When the base station device 3 has made a configuration where theterminal device 1 assumes the joint-coded PDCCH/EPDCCH, the base stationdevice 3 may transmit only the joint-coded PDCCH/EPDCCH, rather thanseparate-coded PDCCHs/EPDCCHs as illustrated in FIG. 11. When the jointcoding is configured, the terminal device 1 may, without expecting theseparate coding, monitor the PDCCH/EPDCCH of the configured downlinkcell.

Specifically, the base station device 3 may make a configuration of, foreach serving cell, whether monitoring is performed in accordance withthe first PDCCH/EPDCCH or the second PDCCH/EPDCCH. The base stationdevice 3 may transmit the higher layer signal including information tobe used for indicating whether monitoring is performed in accordancewith the first PDCCH/EPDCCH or the second PDCCH/EPDCCH. Here, for asingle serving cell, monitoring in accordance with both the firstPDCCH/EPDCCH and the second PDCCH/EPDCCH is not configured. In otherwords, the monitoring in accordance with the first PDCCH/EPDCCH and themonitoring in accordance with the second PDCCH/EPDCCH may not existtogether in a single serving cell. In other words, the terminal device 1may always perform, in a single serving cell, either the monitoring inaccordance with the first PDCCH/EPDCCH or the monitoring in accordancewith the second PDCCH/EPDCCH.

DCI format 6 may be used at least for scheduling of the PDSCH in thesame serving cell, i.e., a cell in which DCI format 6 is transmitted. Inother words, the PDSCH in the serving cell in which DCI format 6 istransmitted is not scheduled in accordance with a DCI format transmittedin a different serving cell from the serving cell. In other words, theserving cell configured to perform the monitoring in accordance with thefirst PDCCH/EPDCCH is not scheduled in accordance with the DCI format(alternatively, the PDCCH may be used) transmitted in the differentserving cell from the serving cell. In other words, the serving cellconfigured to perform the monitoring in accordance with the firstPDCCH/EPDCCH is always scheduled in accordance with the DCI format(alternatively, the PDCCH may be used) transmitted in the serving cell.

Here, DCI format 6 (alternatively, the first PDCCH/EPDCCH may be used)may be received (detected) only in a UE-specific search space (USS). Inother words, DCI format 6 may not be mapped to a common search space(CSS), but may be mapped only to the USS. In other words, the terminaldevice 1 may attempt to decode DCI format 5 (alternatively, the firstPDCCH/EPDCCH may be used) only in the UE-specific search space.

Here, for example, the USS (a position of USS, an index) to which DCIformat 6 is mapped may be calculated (may be given) on the basis of ahash function using at least the C-RNTI and the serving cell index.

As described above, the base station device 3 may configure the multiplePDSCHs scheduled in accordance with a single DCI format 6, by usinginformation included in the higher layer signal. For example, the basestation device 3 may transmit information indicating that the firstPDCCH/EPDCCH (alternatively, DCI format 6 may be used) to be used forthe scheduling of the PDSCH in the downlink cell 5 (for example, servingcell index 1) is transmitted in the downlink cell 5. The base stationdevice 3 may transmit information indicating that the first PDCCH/EPDCCHto be used for the scheduling of the PDSCH in the downlink cell 6 (forexample, serving cell index 2) is transmitted in the downlink cell 5.The base station device 3 may transmit information indicating that thefirst PDCCH/EPDCCH to be used for the scheduling of the PDSCH in thedownlink cell 7 (for example, serving cell index 3) is transmitted inthe downlink cell 5.

The serving cell index used for calculating the USS to which DCI format6 is mapped may be the smallest serving cell index (in this example,serving cell index 1) among the serving cell indexes configured by thebase station device 3. The serving cell index used for calculating theUSS to which the DCI format is mapped may be the largest serving cellindex (in this example, serving cell index 3) among the serving cellindexes configured by the base station device 3. In other words, theserving cell index used for calculating the USS to which DCI format 6 ismapped may be determined on the basis of the information transmitted bythe base station device 3 using the higher layer signal. In other words,the DCI format (the second PDCCH/EPDCCH) used for the scheduling of themultiple PDSCHs in the multiple serving cells may be determined on thebasis of the information transmitted using the higher layer signal.Here, the serving cell index may be the same as the value of the CIFincluded in DCI format 6.

Here, the serving cell index used for calculating the USS to which DCIformat 6 is mapped may be defined in advance in a specification or thelike. For example, the serving cell index used for calculating the USSto which DCI format 6 is mapped may be zero. In other words, the servingcell index may not be used in the calculation of the USS to which DCIformat 6 is mapped.

Here, the value of the CIF used for calculating the USS to which DCIformat 1/1A (the second PDCCH/EPDCCH) is mapped may be determined on thebasis of the serving cell index. For example, when crossing careerscheduling is configured, the value of the CIF included in the DCIformat is used for calculating the USS to which DCI format 1/1A (thesecond PDCCH/EPDCCH) is mapped.

When the crossing career scheduling is not configured, the CIF is notused for calculating the USS to which DCI format 1/1A (the secondPDCCH/EPDCCH) is mapped.

FIG. 12 is a drawing illustrating a configuration where the PDSCH isreceived via the PDCCH/EPDCCH when the cell group is configured.

In FIG. 12, the base station device 3 configures the downlink cell foreach cell group in which the terminal device 1 monitors thePDCCH/EPDCCH. In this case, a single downlink cell is used as amonitoring cell in each cell group, and cell groups may be configured inthe unit of PUCCH transmission (PUCCH cell group), and may be configuredindependently.

Configurations of devices according to the present embodiment will bedescribed below.

FIG. 13 is a schematic block diagram illustrating a configuration of theterminal device 1 according to the present embodiment. As illustrated inFIG. 13, the terminal device 1 is configured to include a radiotransmission/reception unit 10 and a higher layer processing unit 14.The radio transmission/reception unit 10 is configured to include anantenna unit 11, a radio frequency (RF) unit 12, and a baseband unit 13.The higher layer processing unit 14 is configured to include a controlunit 15 and a radio resource control unit 16. The radiotransmission/reception unit 10 is also referred to as a transmissionunit or a reception unit.

The higher layer processing unit 14 outputs uplink data (transportblock) generated by a user operation or the like, to the radiotransmission/reception unit 10. The higher layer processing unit 14performs processing of the medium access control (MAC) layer, the packetdata convergence protocol (PDCP) layer, the radio link control (RLC)layer, and the radio resource control (RRC) layer.

The radio resource control unit 16 included in the higher layerprocessing unit 14 manages various configuration information/parametersof the terminal device 1 itself. The radio resource control unit 16 setsthe various configuration information/parameters in accordance with ahigher layer signal received from the base station device 3.Specifically, the radio resource control unit 16 sets the variousconfiguration information/parameters in accordance with the informationindicating the various configuration information/parameters receivedfrom the base station device 3.

The radio transmission/reception unit 10 performs processing of thephysical layer, such as modulation, demodulation, coding, and decoding.The radio transmission/reception unit 10 demultiplexes, demodulates, anddecodes a signal received from the base station device 3, and outputsthe information resulting from the decoding to the higher layerprocessing unit 14. The radio transmission/reception unit 10 modulatesand codes data to generate a transmit signal, and transmits the transmitsignal to the base station device 3.

The RF unit 12 converts (down-converts) a signal received through theantenna unit 11 into a baseband signal by orthogonal demodulation andremoves unnecessary frequency components. The RF unit 12 outputs theprocessed analog signal to the baseband unit.

The baseband unit 13 converts the analog signal input from the RF unit12 into a digital signal. The baseband unit 13 removes a portioncorresponding to a cyclic prefix (CP) from the digital signal resultingfrom the conversion, performs fast Fourier transform (FFT) on the signalfrom which the CP has been removed, and extracts a signal in thefrequency domain.

The baseband unit 13 performs inverse fast Fourier transform (IFFT) ondata to generate an SC-FDMA symbol, attaches a CP to the generatedSC-FDMA symbol, generates a digital signal in a baseband, and convertsthe digital signal in the baseband into an analog signal. The basebandunit 13 outputs the analog signal resulting from the conversion, to theRF unit 12.

The RF unit 12 removes unnecessary frequency components from the analogsignal input from the baseband unit 13 using a low-pass filter,up-converts the analog signal into a signal of a carrier frequency, andtransmits the final result via the antenna unit 11.

FIG. 14 is a schematic block diagram illustrating a configuration of thebase station device 3 according to the present embodiment. Asillustrated in FIG. 14, the base station device 3 is configured toinclude a radio transmission/reception unit 30 and a higher layerprocessing unit 34. The radio transmission/reception unit 30 isconfigured to include an antenna unit 31, an RF unit 32, and a basebandunit 33. The higher layer processing unit 34 is configured to include acontrol unit 35 and a radio resource control unit 36. The radiotransmission/reception unit 30 is also referred to as a transmissionunit or a reception unit.

The higher layer processing unit 34 performs processing of the mediumaccess control (MAC) layer, the packet data convergence protocol (PDCP)layer, the radio link control (RLC) layer, and the radio resourcecontrol (RRC) layer.

The radio resource control unit 36 included in the higher layerprocessing unit 34 generates, or acquires from a higher node, downlinkdata (transport block) arranged on a physical downlink channel, systeminformation, an RRC message, a MAC control element (CE), and the like,and outputs the generated or acquired data to the radiotransmission/reception unit 30. Furthermore, the radio resource controlunit 36 manages various configuration information/parameters for each ofthe terminal devices 1. The radio resource control unit 36 may setvarious configuration information/parameters for each of the terminaldevices 1 via a higher layer signal. In other words, the radio resourcecontrol unit 36 transmits/broadcasts information indicating variousconfiguration information/parameters.

The capability of the radio transmission/reception unit 30 is similar tothat of the radio transmission/reception unit 10, and hence descriptionthereof is omitted.

However, the capability of the radio transmission/reception unit 10varies among the terminal devices 1. For example, combinations of bands(carriers, frequencies) to which carrier aggregation is applicable varyamong the terminal devices 1. Therefore, the terminal device 1transmits, to the base station device 3, information/parameter(UECapabilityInformation) indicating capability supported by theterminal device 1 itself.

The term “support” means that the terminal device 1 including hardwareand/or software required to implement the capability (or thecommunication method) has passed the conformance test (standardcertification test) specified in 3GPP.

As described above, a terminal device according to the present inventionincludes: a reception unit configured to receive information indicatingthat more than five downlink carriers are configured and informationindicating the number of cells in which the terminal device is capableof simultaneously monitoring physical downlink control channels; and amonitoring unit configured to monitor physical downlink control channelsof cells specified by the information indicating the number of cells inwhich the terminal device is capable of simultaneously monitoringphysical downlink control channels.

A terminal device according to the present invention includes: areception unit configured to receive information indicating that morethan five downlink carriers are configured and information indicatingthe number of downlink cells capable of being activated simultaneously;a medium access control (MAC) layer processing unit configured toactivate downlink cells in accordance with the information indicatingthe number of downlink cells capable of being activated simultaneously;and a monitoring unit configured to monitor physical downlink controlchannels of cells activated by the medium access control (MAC) layerprocessing unit.

A base station device according to the present invention includes: atransmission unit configured to transmit information indicating thatmore than five downlink carriers are configured and informationindicating the number of cells in which a terminal device is capable ofsimultaneously monitoring physical downlink control channels; and aphysical downlink control channel transmission unit configured totransmit physical downlink control channels of cells specified by theinformation indicating the number of cells in which the terminal deviceis capable of simultaneously monitoring physical downlink controlchannels.

A base station device according to the present invention includes: atransmission unit configured to transmit information indicating thatmore than five downlink carriers are configured and informationindicating the number of downlink cells capable of being activatedsimultaneously; a medium access control (MAC) layer processing unitconfigured to activate downlink cells in accordance with the informationindicating the number of downlink cells capable of being activatedsimultaneously; and a physical downlink control channel transmissionunit configured to transmit physical downlink control channels of cellsactivated by the medium access control (MAC) layer processing unit.

A communication method according to the present invention is acommunication method for the terminal device 1. The communication methodincludes the steps of: receiving information indicating that more thanfive downlink carriers are configured and information indicating thenumber of cells in which a terminal device is capable of simultaneouslymonitoring physical downlink control channels; and monitoring physicaldownlink control channels of cells specified by the informationindicating the number of cells in which the terminal device is capableof simultaneously monitoring physical downlink control channels.

A communication method according to the present invention is acommunication method for the terminal device 1. The communication methodincludes the steps of: receiving information indicating that more thanfive downlink carriers are configured and information indicating thenumber of downlink cells in which a terminal device is capable of beingactivated simultaneously; activating downlink cells in accordance withthe information indicating the number of downlink cells capable of beingactivated simultaneously; and monitoring physical downlink controlchannels of the activated cells.

A communication method according to the present invention is acommunication method for the base station device 3 configured tocommunicate with the terminal device 1. The communication methodincludes the steps of: transmitting information indicating that morethan five downlink carriers are configured and information indicatingthe number of cells in which the terminal device is capable ofsimultaneously monitoring physical downlink control channels; andtransmitting physical downlink control channels of cells specified bythe information indicating the number of cells in which the terminaldevice is capable of simultaneously monitoring physical downlink controlchannels.

A communication method according to the present invention is acommunication method for the base station device 3 configured tocommunicate with the terminal device 1. The communication methodincludes the steps of: transmitting information indicating that morethan five downlink carriers are configured and information indicatingthe number of downlink cells capable of being activated simultaneously;activating downlink cells in accordance with the information indicatingthe number of downlink cells capable of being activated simultaneously;and transmitting physical downlink control channels of the activatedcells.

An integrated circuit according to the present invention is anintegrated circuit mounted on the terminal device 1 configured tocommunicate with the base station device 3. The integrated circuitcauses the terminal device to exert the functions of: receivinginformation indicating that more than five downlink carriers areconfigured and information indicating the number of cells in which theterminal device is capable of simultaneously monitoring physicaldownlink control channels; and monitoring physical downlink controlchannels of cells specified by the information indicating the number ofcells in which the terminal device is capable of simultaneouslymonitoring physical downlink control channels.

An integrated circuit according to the present invention is anintegrated circuit mounted on the terminal device 1 configured tocommunicate with the base station device 3. The integrated circuitcauses the terminal device to exert the functions of: receivinginformation indicating that more than five downlink carriers areconfigured and information indicating the number of downlink cellscapable of being activated simultaneously; activating downlink cells inaccordance with the information indicating the number of downlink cellscapable of being activated simultaneously, and monitoring physicaldownlink control channels of the activated cells.

An integrated circuit according to the present invention is anintegrated circuit mounted on the base station device 3 configured tocommunicate with the terminal device 1. The integrated circuit causesthe base station device 3 to exert the functions of: transmittinginformation indicating that more than five downlink carriers areconfigured and information indicating the number of cells in which theterminal device is capable of simultaneously monitoring physicaldownlink control channels; and transmitting physical downlink controlchannels of cells specified by the information indicating the number ofcells in which the terminal device is capable of simultaneouslymonitoring physical downlink control channels.

An integrated circuit according to the present invention is anintegrated circuit mounted on the base station device 3 configured tocommunicate with the terminal device 1. The integrated circuit causesthe base station device 3 to exert the functions of: transmittinginformation indicating that more than five downlink carriers areconfigured and information indicating the number of downlink cellscapable of being activated simultaneously; activating downlink cells inaccordance with the information indicating the number of downlink cellscapable of being activated simultaneously, and transmitting physicaldownlink control channels of the activated cells.

A program running on each of the base station device 3 and the terminaldevice 1 according to the present invention may be a program thatcontrols a central processing unit (CPU) and the like (a program forcausing a computer to operate) in such a manner as to realize thefunctions according to the above-described embodiments of the presentinvention. The information handled in these devices is temporarilystored in a random access memory (RAM) while being processed.Thereafter, the information is stored in various types of read onlymemory (ROM) such as a flash ROM and a hard disk drive (HDD) and whennecessary, is read by the CPU to be modified or rewritten.

Moreover, the terminal device 1 and the base station device 3 accordingto the above-described embodiments may be partially realized by thecomputer. This configuration may be realized by recording a program forrealizing such control functions on a computer-readable medium andcausing a computer system to read the program recorded on the recordingmedium for execution.

The “computer system” refers to a computer system built into theterminal device 1 or the base station device 3, and the computer systemincludes an OS and hardware components such as a peripheral device.Furthermore, the “computer-readable recording medium” refers to aportable medium such as a flexible disk, a magneto-optical disk, a ROM,and a CD-ROM, and a storage device such as a hard disk built into thecomputer system.

Moreover, the “computer-readable recording medium” may include a mediumthat dynamically retains the program for a short period of time, such asa communication line that is used to transmit the program over a networksuch as the Internet or over a communication line such as a telephoneline, and a medium that retains, in that case, the program for a certainperiod of time, such as a volatile memory within the computer systemwhich functions as a server or a client. Furthermore, the program may beconfigured to realize some of the functions described above, andadditionally may be configured to realize the functions described abovein combination with a program already recorded in the computer system.

Furthermore, the base station device 3 according to the above-describedembodiments can be realized as an aggregation (a device group)constituted of multiple devices. Devices constituting the device groupmay be each equipped with some or all portions of each function or eachfunctional block of the base station device 3 according to theabove-described embodiments. It is only required that the device groupitself include general functions or general functional blocks of thebase station device 3. Furthermore, the terminal device 1 according tothe above-described embodiments can communicate with the base stationdevice as the aggregation.

Furthermore, the base station device 3 according to the above-describedembodiments may be an Evolved Universal Terrestrial Radio Access Network(EUTRAN). Furthermore, the base station device 3 according to theabove-described embodiments may have some or all portions of thefunction of a node higher than an eNodeB.

Furthermore, some or all portions of each of the terminal device 1 andthe base station device 3 according to the above-described embodimentsmay be realized as an LSI that is a typical integrated circuit or may berealized as a chip set. The functional blocks of each of the terminaldevice 1 and the base station device 3 may be individually realized as achip, or some or all of the functional blocks may be integrated into achip. Furthermore, the circuit integration technique is not limited tothe LSI, and the integrated circuit may be realized with a dedicatedcircuit or a general-purpose processor. Furthermore, if with advances insemiconductor technology, a circuit integration technology with which anLSI is replaced appears, it is also possible to use an integratedcircuit based on the technology.

Furthermore, according to the above-described embodiments, the terminaldevice is described as one example of a communication device, but thepresent invention is not limited to this, and can be applied to afixed-type electronic apparatus installed indoors or outdoors, or astationary-type electronic apparatus, for example, a terminal device ora communication device, such as an audio-video (AV) apparatus, a kitchenapparatus, a cleaning or washing machine, an air-conditioning apparatus,office equipment, a vending machine, and other household apparatuses.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Furthermore, various modifications are possiblewithin the scope of the present invention defined by claims, andembodiments that are made by suitably combining technical meansdisclosed according to the different embodiments are also included inthe technical scope of the present invention. Furthermore, aconfiguration in which a constituent element that achieves the sameeffect is substituted for the one that is described according to theembodiments is also included in the technical scope of the presentinvention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 (1A, 1B, 1C) Terminal device    -   3 Base station device    -   5 Downlink cell    -   6 Downlink cell    -   7 Downlink cell    -   10 Radio transmission/reception unit    -   11 Antenna unit    -   12 RF unit    -   13 Baseband unit    -   14 Higher layer processing unit    -   15 Control unit    -   16 Radio resource control unit    -   30 Radio transmission/reception unit    -   31 Antenna unit    -   32 RF unit    -   33 Baseband unit    -   34 Higher layer processing unit    -   35 Control unit    -   36 Radio resource control unit

1. A terminal device configured to communicate with a base stationdevice, the terminal device comprising: reception circuitry configuredto receive first information indicating that more than five cells areconfigured, and second information indicating the number of physicaldownlink control channels that the terminal device is able tosimultaneously monitor; and monitoring circuitry configured to monitorphysical downlink control channels, the number of which is specified bythe second information.
 2. (canceled)
 3. A base station deviceconfigured to communicate with a terminal device, the base stationdevice comprising: first transmission circuitry configured to transmitfirst information indicating that more than five cells are configured,and second information indicating the number of physical downlinkcontrol channels that the terminal device is able to simultaneouslymonitor; and second transmission circuitry configured to transmitphysical downlink control channels, the number of which is specified bythe second information.
 4. (canceled)
 5. A communication method for aterminal device configured to communicate with a base station device,the communication method comprising: receiving first informationindicating that more than five cells are configured, and secondinformation indicating the number of physical downlink control channelsthat the terminal device is able to simultaneously monitor; andmonitoring physical downlink control channels, the number of which isspecified by the second information.
 6. (canceled)
 7. A communicationmethod for a base station device configured to communicate with aterminal device, the communication method comprising: transmitting firstinformation indicating that more than five cells are configured, andsecond information indicating the number of physical downlink controlchannels that the terminal device is able to simultaneously monitor; andtransmitting physical downlink control channels, the number of which isspecified by the second information.
 8. (canceled)
 9. An integratedcircuit mountable on a terminal device configured to communicate with abase station device, the integrated circuit causing the terminal deviceto perform at least: receiving first information indicating that morethan five cells are configured, and second information indicating thenumber of physical downlink control channels that the terminal device isable to simultaneously monitor; and monitoring physical downlink controlchannels, the number of which is specified by the second information.10. (canceled)
 11. An integrated circuit mountable on a base stationdevice configured to communicate with a terminal device, the integratedcircuit causing the base station device to perform at least:Transmitting first information indicating that more than five cells areconfigured, and second information indicating the number of physicaldownlink control channels that the terminal device is able tosimultaneously monitor; and transmitting physical downlink controlchannels, the number of which is specified by the second information.12. (canceled)